What Laura said. :-) FTDNA accepts both V1 and V2 AncestryDNA autosomal test results uploads into a free account. The cost to activate the account for matching and comparisons in $19. Worth it: not only gives potentially additional atDNA matches, but if any exact 37-marker yDNA matches surface it might also provide a correlation to the individual via atDNA, allowing you to predict degree of cousinship.
Once the account is established for your brother, you can use that account (he'll keep the same FTDNA Kit Number throughout, BTW) when sale-time comes to purchase the new Y-37 test. Unlike GEDmatch, there can't be multiple test kits under the same kit number (account ID) at FTDNA. When you purchase the new yDNA test from the new account's profile page, they'll send out a cheek-swab set and everything proceeds from there normally.
P.S. The greatest factor of longevity of the sample sent to FTDNA (how long the sample will remain viable and how many future tests can be processed without submitting a new sample) is the diligence of the cheek swabbing. The instructions will describe the simple process, but they recommend 30 seconds per swab per cheek. Tell your brother to ignore that and give 'em 60 seconds of attention each, and to not just scrape but to twist to Q-tip-like thingy at the same time. With very good swabbing technique, there's no reason that sample can't remain viable for a quarter of a century and many future upgrades.